Standardized optical disk storage formats have recently evolved from Digital Versatile Disk (DVD) to Blu-ray. A Blu-ray disk is read using a blue laser having a wavelength of 405 nanometers, significantly shorter than the 650 nanometer red laser used to read DVDs. Information can therefore be stored at a much higher density on Blu-ray disks. For example, a single layer Blu-ray disk can store about 25 Gigabytes (GB) of data, compared to about 5 GB for a DVD. Higher storage densities can be achieved by configuring the optical disk to include multiple storage layers, as is well known.
Although Blu-ray disks have the advantage of higher storage density, the use of a shorter wavelength laser for readout can also be problematic in that it leads to a higher susceptibility to playback errors arising from scratches, fingerprints, dust particles, bubbles or other imperfections on or near the disk surface.
Depending on the extent of the surface imperfection, playback by an optical disk playback device can be briefly interrupted or stopped all together. For small imperfections, the playback device will typically first attempt to re-read the data that is in error, and if it cannot re-read the data, the device may skip ahead and try to read the next data location, continuing this process until the surface imperfection is finally bypassed and normal playback resumes. For larger imperfections, the playback oftentimes freezes completely, as the correction process implemented in the playback device cannot resolve the situation. The user may then have to use a “skip” or “fast forward” feature of the playback device in order to manually step ahead in the playback sequence, until the surface imperfection is bypassed.